1. Field of the Invention
The present invention relates to a graphic object designating apparatus, a graphic object designating method and a graphic object designating program for designating graphic objects to be edited on a display screen of a graphics editing system that edits graphic objects by using a GUI (Graphical User Interface).
2. Description of the Related Art
A conventional graphics editing system and graphic object designating apparatus will be described below. The graphics editing system edits a combination of various types of graphic objects. Objects to be edited are displayed on a display screen of the graphics editing system. For example, rectangular objects and circular objects are displayed on the display screen. When performing some processing on objects, first, the operator of the graphics editing system designates objects to be processed by using a graphic object designating apparatus connected to the graphics editing system. When the graphics editing system is informed of the designated objects, the desired processing is executed. For example, the method of designating objects is as follows. The operator moves a mouse to move the mouse cursor onto a desired object and pushes a button provided on the mouse, thereby designating the object that the mouse cursor points to.
Let us explain a graphic object designating operation using a logic circuit designing CAD (Computer Aided Design) system as a specific example of the conventional graphics editing system. In the logic circuit designing CAD system, logic symbols and terminals thereof are displayed on a display screen. Designing of a logic circuit is performed by using a graphic object designating apparatus connected to the logic circuit designing CAD system. That is, a terminal of one logic symbol and a terminal of another logic symbol are designated with a mouse cursor, thereby designating wiring between the terminals.
FIG. 23 is a diagram showing an example of a logic symbol and a mouse cursor. On the display, a large number of logic symbols such as the one 81 shown in FIG. 23 by way of example are displayed, together with a mouse cursor 80, e.g. an arrow. The operator moves the mouse cursor 80 to the position of a desired terminal, e.g. terminal 82, of a desired logic symbol on the display by using a mouse, for example, and pushes a button provided on the mouse in this state to transmit a trigger to the graphic object designating apparatus. Thus, the terminal that the mouse cursor points to is designated. In response to designation made with respect to two terminals in this way, the graphics editing system wires the designated terminals to each other on the display, thereby connecting them together on a net of signal lines.
It should be noted that Japanese Patent Application Unexamined Publication (KOKAI) No. Hei 6-187394 (p. 2-3, FIG. 1) is known as an example of terminal designating apparatus for designating terminals in designing of an LSI logic circuit. According to the terminal designating apparatus, the mouse cursor is moved circularly from one terminal to another of a symbol designated by the operator, thereby facilitating designation of terminals.
However, the object designating method using the mouse cursor involves the following problems. First, when objects displayed on the display screen are small in size, it is difficult for the operator to designate them. For example, in the above-described CAD system for designing an LSI logic circuit, a logic circuit including a large number of logic symbols is displayed on the display screen. Therefore, the display size of each logic symbol is very small, and the display size of each individual terminal is even smaller. The operator may take much time to accurately point the mouse cursor at the position of a desired terminal or may mistakenly designate a terminal adjacent to the desired one. In such a case, the conventional practice is to zoom into a desired area of the display screen to thereby enlarge the display size of logic symbols displayed before designating terminals of the logic symbols. Further, it may necessary to restore the display size to the previous one after designating objects.
When performing an operation in an environment where the mouse cursor is difficult to move freely, it is difficult for the operator to designate objects. For example, when objects are designated by moving the mouse cursor using a touch pad on a notebook-model personal computer, it is difficult to make object designation.
When various types of objects are displayed, it is difficult for the operator to designate desired objects. For example, when three different types of objects, e.g. rectangular objects, circular objects, and linear objects, are displayed, it is difficult to designate only linear objects.
Further, in the above-described terminal designating apparatus, the mouse cursor is moved to all terminals circularly in one direction. Therefore, when a very large number of terminals are present, it takes time and labor to move the mouse cursor to a desired terminal.